Step 1: Preheat your oven to 350°F (175°C) and generously grease a 9-inch square baking pan or a decorative pudding mold.
Step 2: In a medium bowl, sift together the all-purpose flour, baking powder, baking soda, cinnamon, grated nutmeg, and salt to ensure even distribution of spices.
Step 3: In a large mixing bowl, cream the softened butter and brown sugar together using an electric mixer until the mixture is light, fluffy, and pale in color.
Step 4: Beat in the eggs one at a time, ensuring each is fully incorporated before adding the next, then stir in the vanilla extract.
Step 5: Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined. Do not over-mix the batter.
Step 6: Using a rubber spatula, gently fold in the finely grated carrots, chopped dates, and raisins until they are evenly distributed throughout the batter.
Step 7: Pour the batter into the prepared baking pan, smoothing the top with your spatula, and bake for 45 to 50 minutes or until a toothpick inserted into the center comes out clean.
Step 8: While the pudding is cooling slightly, prepare the nutmeg cream by whipping the heavy cream, powdered sugar, and 0.25 tsp of nutmeg until soft peaks form. Serve the warm pudding with a generous dollop of the cream.